Analysis of iterative design algorithms for achromatic deterministic diffusers

Abstract

Almost achromatic off-axis deterministic diffusers are flexible micro-optical elements that can produce arbitrary light distributions. They can, for example, increase the efficiency of projection systems when used as screens. These elements still pose a challenge in both design and manufacturing due to the often occurring necessity of a tessellated surface. We estimate the element depth necessary to achieve achromatic behavior using a blazed grating as a substitute model. We then show the design of a tessellated, deep diffuser using an algorithm published by Brenner [Opt. Lett. 25, 31 (2000)OPLEDP0146-959210.1364/OL.25.000031]. To further enhance the diffraction efficiency under manufacturing constraints, we introduce a modification that preserves the tessellation edges during design. We show that the modified algorithm yields an increase in efficiency and demonstrate the quasi-achromatic behavior of the resulting height profile.